The present invention relates to an optical element and in particular is intended to relate to an optical element which is capable of transmitting electromagnetic radiation and in so doing capturing from the incident radiation a range or number or ranges of wavelengths and redirecting at least some of the eliminated radiation from the optical element in a controlled manner.
Throughout the specification the term "optical element" is not to be limited to one for use with the visible spectrum but is applicable to all forms of electromagnetic radiation including, but not limited to, microwave, infrared, visible, ultraviolet, X and gamma radiation.
In the past it has been known to provide luminescent materials which are capable of absorbing selected wavelengths or ranges of wavelengths of electromagnetic radiation such as visible light, infra-red radiation, ultraviolet radiation, X-radiation and the like and remitting at a different wavelength or range of wavelengths. Such materials can comprise organic dyes or similar organic compounds as well as inorganic compounds such as salts of rare earth elements.
It is an object of the invention to provide an optical element which has the capacity to intercept some of the electromagnetic radiation incident on the optical element and to redirect such radiation into the interior of the optical element to be able to be emitted from the optical element separately from the remaining transmitted radiation.
Accordingly the invention resides in an optical element comprising a plurality of transparent layers comprising one or more passive layers and one or more active layers wherein said passive layers facilitate the transmission of electromagnetic radiation in a substantially unaltered form and the at least one active layers include an active material dispersed through the active layer and having the capacity to intercept electromagnetic radiation of at least one first predetermined wavelength or range of wavelengths and redirect at least a portion of energy of the intercepted radiation into the interior of the optical element said layers being in face to face relationship and being optically coupled to each other.
According to a preferred feature the active material may comprise substances or particles which are reflective and/or dispersive in relation to at least a portion of the intercepted radiation.
It is a preferred object of the invention to provide a transparent optical element which can utilise the properties of luminescent materials to eliminate from the incident radiation, the selected wavelengths or ranges of wavelengths.